MgO template effect for perpendicular magnetic anisotropy in (001)-textured poly-crystalline MnAlGe films

Magnetic thin films showing high perpendicular magnetic anisotropy, K-u, and low saturation magnetization, M-s, are essential for realizing a small switching current in spintronic devices utilizing the current induced magnetization switching phenomena. The Cu2Sb-type MnAlGe intermetallic compound is a material showing uniaxial magnetocrystalline anisotropy with a relatively low M-s, which is attractive for spintronic application. In this study, the layer thickness dependence of K-u was investigated in poly-crystalline MnAlGe films, and the MgO template effect is discussed to achieve perpendicularly magnetized films in a few-nanometer thickness range. Experimental results suggested that the (001)-texture for the perpendicular magnetization was promoted by the MgO(001) template through the solid-phase epitaxy growth by annealing, which is similar with that in conventionally used CoFeB|MgO layered samples. K-u of about 2 x 10(6) erg/cm(3) was achieved in a 5 nm-thick MnAlGe film using MgO buffer and capping exhibiting a low M-s value of approximately 200 emu/cm(3) at room temperature. Although the magnitude of K-u is still in a moderate range, the low M-s is a promising feature for spintronic application.